As described by Matz, Snack Food Technology, conventional corn chip processes begin with a corn meal or corn masa. Both white and yellow corn kernels of the dent type are added to a vat containing water and a proportionate amount of lime. The mixture is heated to the boiling point, the heat is cut off, and the contents of the vat are allowed to stand undisturbed for up to 10 to 20 hours. During this heating and steeping stage, the corn hulls are hydrated and partially hydrolyzed. This softens the hulls to a jelly-like consistency and they are easily removed and discarded later in the process. Some of the starch in the corn also becomes gelatinized. By the end of the steeping period, the corn kernels have absorbed about 50% by weight water. The hulls are removed in a washer by jets of water which also remove excess lime. The washed kernels are then normally, but not necessarily, transferred to a stone mill where they are ground into dough or masa. The masa is formed (usually by hand) into large loaves and then fed into hydraulically powered extrusion presses. To produce a more tender product, relatively low amounts of work input are used to form the dough pieces from the loaves. The cylindrical chamber of the press contains a closely fitting piston which forces the dough through a die plate having a series of slot-like ports about 1/2 inch (1.27 cm) wide, a cutting device severs the extruded strands into pieces, usually about 11/2 inch (3.81 cm). In the alternative, the dough can be rolled out into thin sheets from which shapes can be cut. In either case, the dough pieces travel directly into cooking oil held at about 375.degree. F. (190.6.degree. C.). After the moisture content has been reduced to a few percent, the chips are removed from the oil, salted, cooled, and packaged.
Conventional processes for producing corn chips, similar to that described above, have the disadvantage of producing chips that are hard, gritty, and do not easily melt in the mouth.
Several patents disclose corn chips made with various additives.
For example, U.S. Pat. No. 3,368,902 to Berg discloses a process for making corn chips in which ground corn or masa is cooked until substantially full gelatinization of all corn starch occurs before frying. In a preferred embodiment extra corn starch and carboxymethylcellulose are added to the dough after cooking but before frying. The advantages are said to be improved texture and reduced oil absorption. Calcium hydroxide at a 1.0% to 1.5% level based on dry corn is said to bring out greater corn flavor. Emulsifiers are not disclosed.
U.S. Pat. No. 4,645,679 to Lee et al. discloses the production of corn chips having potato chip-like texture. This is accomplished by combining ground hydrated corn with a starch material, extruding the mixture into a dough, and frying. The resultant chip is said to have moderate corn taste, yet have a texture that is light and crisp.
U.S. Pat. No. 4,219,580 to Torres discloses the use of edible, non-digestible flour substitutes such as microcrystalline cellulose in baked goods to reduce the caloric value of those goods. Also disclosed is the use of emulsifiers such as lecithin, glycerol derivatives (for example, glycerol monoesters, partially acetylated glycerol monoesters, mono-and diglyceride mixtures, partially acetylated mono- and diglycerides, and polyglycerol monoesters), lactylated fatty acids, and sorbitan derivatives. Preferred emulsifiers are lecithin, mono-diglyceride mixtures, sodium steroyl-2-lactylate and triglycerol monostearate. No disclosure is made for use in corn chips.
U.S. Pat. No. 4,517,204 to Mottur et al. discloses a process for the production of puffed snack foods in which coated microcrystalline cellulose is added to the dough prior to puffing in the ratio of meal or flour to cellulose of from about 9:1 to about 3:1. Emulsifiers, such as lecithin, and mono- and diglycerides can be added from about 0.1% to about 1.0% by weight to improve expansion of the final product. The cooking stage is carried out in an extruder to form collets which expand upon frying or baking.
U.S. Pat. No. 4,502,479 to Singer et al. discloses a process for producing snack food products in which a pregelatinized starch (potato is preferred, and only potato, rice and wheat are disclosed) is mixed with water and an emulsifying gel containing saturated monoglycerides.
U.S. Pat. No. 4,568,557 to Becker et al. discloses snack food products containing high dietary fiber contents. A fat-based coating is applied to the dietary fibers to aid as a binder, protect the fibers from excess moisture, to aid in dough processing, and mask any undesirable textural quality associated with the fibers. The coating can contain emulsifiers. Specifically disclosed emulsifiers are lecithin and mono- and diglycerides.
U.S. Pat. No. 4,568,550 to Fulger et al. discloses extrusion cooking of flour-based doughs. Use of sodium steroyl-2-lactylate and glyceryl monostearate as conditioning agents is disclosed. Also disclosed, but not exemplified, is the possible inclusion of cellulose or other dietary fibers.
U.S. Pat. No. 3,998,975 to Liepa discloses doughs made from dehydrated potatoes that contain 0.4% to 1.0% monoglycerides to improve the texture of the reconstituted mash.
It is an object of this invention to produce unique cereal-based snack chips having a high degree of crispness and crunchiness without sacrificing textural lightness.
It is another object of this invention to produce cereal-based snack chips which are lower in fat and higher in fiber than traditional snack chips.
It is another object of this invention to describe various emulsifiers and combinations of emulsifiers which when incorporated into a cereal-based composition produce a unique snack chip that is texturally light yet more crunchy than snack chips with comparable lightness.
It is another object of this invention to describe an absorbent material which, when incorporated into a cereal-based composition, improves crunchiness in the final chip.
It is still another object of this invention to describe process conditions by which the cereal-based composition and the resultant chips can be produced.
These and other objects will become apparent by the description of the invention below.